S. 153A: Assessment-Search-Unexplained expenditure-Payment of commission-Bogus sales-Gross profit offered to tax-Gross profit is available to set off-Unaccounted advances paid to employees-Only remaining amount is taxable-Stock-Valuation at average rate of method is acceptable-Addition is deleted-Undisclosed income is accepted-Further addition towards purchases is not justified. [S. 69, 69C, 132, 133]